This a good question, many customers do not recognize or find the importance of having a website secure, they just publish their websites without any security consideration.
Having an SSL in your website is important because guarding the communications is a tool to prevent phishing practices. (read this article please http://resources.infosecinstitute.com/phish-like-hacker-securityiq). With an SSL certificate on your website, you can prevent this kind of problems or reduce it significantly.
When should I put a certificate on my website?